Method of and apparatus for treating water



Dec. 31, 1940. R. RILEY 2,226,743

METHOD OF AND APPARATUS FOR TREATING WATER Filed Dec 16, 1939 INVENTOR. RAY RILEY A TTORNEY METHOD or APPARATUS you, shearme wanna Ray Riley, gham, N. 3., assignor to The lermutit Company, New York, N. Y a corporation of Delaware Application Decemberlfi, 1939, Serial No. 309,523 8 Claims. ((31. 210-24) This invention relates to method of and-apparatus for treating water; and it comprises passing a flow of water to be treated through hydrogen zeolite, then dividing the flow into two streams and g one oi said streams with the now more recent carbonaceous type which are reldl sistant to acid and may be regenerated with acid to function as hydrogen ion exchange materials.

Waters containing appreciable amounts of phenolphthalein alkalinity rarely occur in nature. Many municipm water supplies, however, are so given phenolphthaleln alkalinity by feeding to them alkali such as hydrate oi limeinorder to protect the pipe distribution system against corrosive attack. When such water or a natural water with phenolphthalein alkalinity is passed as through zeolite for ion exchange the useful life of the zeolite is shortened. Moreover, when a water having phenolphthalein alkalinity is passed through a bed of zeolite of the carbonaceous or greensand type the color of the water freso quentLv increases noticeably due to a pickup of I color from the zeolite. In some industries, such as textile or rayon industries, a water free or color ls a necessity, and in many uses, such as for household purposes, colored water is highly 85 undesirable.

'Bie phenolphthalein alkalinity of a water supply may be neutralized by feeding an acid, such' 7 as sulfuric acid, in appropriate proportional amolmts but this involves a. continuing operating 40 expense forthe purchase of acid, it requires equipment for accurately feeding the acid, and it also increases the total solids content of the water.-

- Another method of reducing phenolphthalein alkalinlty is to carbonate the water by blowing C'Oz 4,5 through it to combine with carbonate and form bicarbonate which is harmless to zeolites. This method, however, also necessitates relatively complicated equipment which is high in initial cost as well as upkeep and requires careful and ireao quent attention in order to maintain uniform results.

The obiects of this invention are first, to neutralize phenolphthalein alkalinity of a water supply mice to e through zeolite without inthe negative ion or total solids content;

secondly, to accomplish this neutralization with equipment of utmost simplicity which is inexpensive in first cost as well as in'operation'and which requires little attention.

'Ihe manner in which these objects are achieved is illustrated in the appended drawing in which- Fig. 1 is a diagrammatic view in elevation, partly in cross-section, of an apparatus in accordance with my invention andadaptedto carry out the method of treating water in accordance with my invention; and

Fig. 2 is a modification of the apparatus shown inilg. l.

Similar reference numerals refer to shnilar parts throughout both views.

Referring nowto Fig. l, a tank ill contains a bed ll of carbonaceous zeolite having hydrogen as its base, briefly termed hydrogen zeolite. A

,muitiport valve l2, advantageously of the type' described in the patent to E. Staegemann No.3!) 2,051,155, dated Aug. 18, 1936, is provided to diroot the flow through the tank. The valve l2 has a water inlet i3, a connection l4 leading to the top of the tank l5, :3. connection I5 leading to tank Ill below the bed. ii, an outlet l5, and a pair of waste outlets El and, It. The valve i2 is, furthermore, connected to an injector l9 having a discharge 2!? leading into tank 80 above the bed ii, and a suction connection 25 fitted with a valve 22 and leading to a tank 23 for dilute sulfuric acid. 'I'hewater inlet l3 is provided with an individual valve 26.

A second tank 30 contains a bed 3| of zeolite of any desired type having sodium as its base,

termed sodium zeolite, and has a multiport valve 5 32-01 similar construction as valve 42 referred to above. vVa1ve'32 has a water inlet 33 with anindividual valve 44, a connection 34 leading to the top of tank 30, a connection 35 leading to tank 30 below the bed 3|, an outlet 36, and a pair 01' waste outlets 31- and 38. The valve 32 is, furthermore, connected to an injector 39 having a discharge 40 leading into tank 30 above the bed 3|, and a suction connection 4| .fltted with a valve 42 and leading to a brine tank- 43. 45

A supply pipe 48 for water to be treated is connected to water inlets l3 and 33, and a service pipe 49 is arranged to receive treated water from outlets'lS and 36. The apparatus described thus for is '0! known construction. In place of the so inultiport valves 12 and 33 nests of individual valves may, of course, be employed.

According to my invention 1 provide a branch pipe 5 leading from the outlet 16 to a pump M f V which in-turn has a discharge pipe 52 fitted with s5 p adapted to maintain a flow of water from pipe [6 through pipes 50 and 52 to supply pipe 48.

This flow may be regulated by adjustment of valve 53.

Operation of this apparatus is as follows. A stream of water to be treated flows from the supply pipe 58 through inlet i3, valve I2, and connection i l to the top of tank l0, passes downwardly through the bed H of hydrogen zeolite, and leaves the tank through connection 15, valve i2, and outlet i8. Simultaneously a second stream flows from pipe i8 through inlet 33, valve 32 and connection as to the top of tank 35, passes downwardly through the bed 3i of sodium zeolite, and then leaves tank til through connection 35, valve 32 and outlet 36. A portion of the treated water flowing through pipe it passes through branch pipe 56 to the pump 5! which discharges this portion through pipe 52 into the supply pipe i8. This portion of recycled treated water thus is mixed with the water to be treated before it is divided into the two streams passing through tanks [fl and 30, respectively. The remainder of the water flowing through outlet it, together with the stream passing through outlet 36 is sent to a point of use through pipe at.

When the zeolites in tanks id and 30 have become exhausted they are regenerated by operating valves i2 and 32, either manuallyor automatically, as described in the Staegemann patent referred to above. The zeolite is first backwashed by an upward flow of water, then brought in contact with dilute acid from tank 23 'or with sodium chloride solution from tank t3, respectively, and finally rinsed free of excess acid or brine, respectively, the efiiuent during regeneration passing through outlets ll, l8 and 31, 38, respectively, to waste. Upon completion of the regeneration process the units are returned to service by a further movement of valves 12 and 32.

The apparatus shown in Fig. 2 is similar to the apparatus of Fig. 1 except that in place of the pump 5| with its connections 56 and 52 an injector 60 is placed in the supply pipe it. This in- 1 jector 6D has a suction pipe 5! connected through valve 52 and check valve 63 with the outlet l6. When water flows through pipe 48 a suction is producedby the injector 60 so that a portion of the treated water is re-cycled from outlet l6 through suction pipe Bl to supply pipe 48 to mix with'the water flowing therethrough. At times when there is no flow through pipe 48 the check valve 63 prevents a flow of untreated water from the supply pipe 48 through suction pipe 6| to outlet IG. In all other respects the operation of the apparatus shown in Figs. 1 and 2 is alike.

In the apparatus of Fig. 2 other types of jet pumps may be used in place of the injector, such as a Venturl tube with the suction connection at the throat, or an orifice plate with the suction connection at=-the location of the vena contracta. A jet type pump is advantageous when some loss in pressure of the water to be treated is permissible because it is relatively in expensive, requires no outside energy, and has no moving parts.

The relative quantities of water to be treated by hydrogen zeolite and by sodium zeolite are regulated by:- a suitable adjustment of valves 24 and 44, while the rate of flow of recycled treated water is regulated by means of valve 53 or 62, respectivey. whi f desired. y be replaced by a rate of flow controller.

Theefiectiveness of my method of pre-treating the water is best illustrated by an example. Let it be assumed that the water to be treated is of the character shown in line A ofthe following table. This water has a phenolphthalein alkalinity of 40 parts per million. Such water will, in a relatively short time, attack any of the zeolites known at present (although some types are somewhat more resistant to such attack than others), thus seriously shortening the useful life of the zeolite and also causing the water to become contaminated by matter leached out of the zeolite.

Analysis in parts per million expressed as CaC'O;

After this water has been passed through hydrogen zeolite it is of the character shown in line B; in place of alkalinity the water now has parts per million of free mineral acidity.

Ii 31 parts of this hydrogen zeolite treated water are re-cycled and mixed with 100 parts of untreated water a mixture results as shown in line C. Both hardness and methyl orange alkalinity of this mixture are slightly lower than in the untreated water, and there is neither any phenolphthalein alkalinity nor, of course, free mineral acidity. Such water can safely be passed through zeolite; it will not attack the zeolite and, consequently, will not become contaminated with color as a result of any breaking down of the zeolite grains. Line D of the table shows the character of the water treated with sodium zeolite. If 27 parts of this water are mixed with the remaining 73 parts of hydrogen zeolite treated water the resultant mixture, as shown in line E, has 15 parts per million of methyl orange alkalinity, and neither hardness, nor phenolphthalein alkalinity, nor free mineral acidity. After removing from this mixture the carbon dioxide by the simple expedient qi aeration it is excellently suited for most uses. A methyl orange alkalinity higher or lower than 15 is readily obtainable by changing the rate of sodium zeolite efliuent to hydrogen zeolite eflluent. In cases where the proportion of water to be sodium zeolite treated is small, especially when the total quantity of water to be treated is likewise small, it is sometimes more convenient to eliminate the sodium zeolite softener altogether, and to neutralize the free mineral acidity of the hydrogen zeolite treated water by feeding appropriate amounts of caustic soda. In, such cases only a single stream of water passing to a hydrogen zeolite softener is pretreated by re-cycling a portion of the efiluent according to my invention.

As shown by the foregoing example, my method of pretreating a water having phenolphthalein alkalinity removes this alkalinity without adding anything to the water and without in any way ailecting the character of the water -be exact.

sent to use. It involves a minimum of equipment; and, once adjusted, the re-cycling requires no attention. The adjustment need not If somewhat more is re-cycled than is necessary for neutralization of the phenolphthalein alkalinity then there will be a further reduction in the methyl orange alkalinity of the water to be softened which is not objectionable; if, on the other hand, somewhat less is re-cycled then a small amount of phenolphthalein alkalinity will be left in the water to, be passed through the zeolite, but small amounts of such alkalinity have no noticeably harmful effect.

Modifications of the apparatus illustrated and described herein may occur to others without departing from the spirit of my invention, and reference is, therefore, made to the following claims for a definition of the scope of my invention.

What I claim is:

1. A method of treating water which comprises passing a flow of water to be treated through hydrogen zeolite, then dividing the flow into two streams, and mixing one of said streams with the flow of water to be treated prior to passing said flow through hydrogen zeolite.

2. A method of treating water having phenolphthalein alkalinity which comprises passing a flow of said water through .hydrogen zeolite whereby the water becomes acid, and mixing suificient of said acid water with the alkaline water prior to passing it through hydrogen zeolite to produce a mixture. having a phenolphthalein alkalinity of approximately zero.

3. A method of treating water which comprises dividing a flow of water to be treated into two stream passing one of said streams through sodium zeo ite, passing the other stream through hydrogen zeolite, then dividing said other stream into two portions, mixing one of said portions with the flow of water to be treated, and mixing the other portion with the stream passed through sodium zeolite.

' outlet pipe to the supply pipe.

4. A method of treating water having phenolphthalein alkalinity which comprises adding to a flow of said water a suflicient flow of acid water to produce a mixture having a phenolphthalein alkalinity of approximately zero, dividing the resultant mixture into two streams, passing one stream through sodium zeolite, passing the other stream through hydrogen zeolite wherebythe water becomes acid, then diverting a portion of said other stream to form said flow of acid water, and combining the remainder of said other stream with the first named stream after water supply pipe, and means for establishing through said conduit a flow-of water from the 6. The combination of claim 5, the means for establishing flow being apump in the conduit.

7. The combination of claim 5, the means for establishing flow being a jet pump in the supply pipe.

8. In an apparatus for treating water comprising a tank, a bed of hydrogen zeolite in said tank, a second tank, a bed of sodium zeolite in the second tank, a water supply pipe connected with both said tanks, an outlet pipe leading to a point of use, a branch pipe connecting the first named tank with the outlet pipe, and a second branch pipe connecting the second tank with the outlet pipe, an improvement which comprises a conduit connecting the first named branch pipe with the supply pipe, and means for establishing through said conduit a flow of water from the first named branch pipe to the 

